Pore-structure optimization of calcium carbonate for enhanced sulfation
Pore-structure optimization of calcium carbonate for enhanced sulfation
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DOI：
10.1002/aic.690430917
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发表时间：
1997-09
期刊：
影响因子：
3.7
通讯作者：
S. Mahuli;R. Agnihotri;Shriniwas S. Chauk-;A. Ghosh-Dastidar;S. Wei;L. Fan
中科院分区：
文献类型：
--
作者：
S. Mahuli;R. Agnihotri;Shriniwas S. Chauk-;A. Ghosh-Dastidar;S. Wei;L. Fan
制备了一种具有开孔内孔结构的改性碳酸钙脱硫剂，并在气流床反应器中考察了该脱硫剂在高温(90 0~1 100℃)和短接触时间(20~600ms)下的硫化特性。这种改性碳酸盐(MC)的最大特点是在0.5S范围内有70%-75%的硫酸盐转化率，大大高于已发表的任何其他脱硫剂。通过优化操作参数，从氢氧化钙悬浮液中碳化-沉淀制备MC，以生成具有所需孔结构特性的碳酸盐颗粒。较高的初始比表面积与其开孔结构和焙烧的孔径分布相结合，使其具有较高的反应活性。焙烧后的MC具有50-200A范围内相当大的孔体积。该尺寸范围代表了硫酸盐化的最佳孔尺寸，因为它提供了相当高的表面积，并且比<；50A孔尺寸更不容易受到孔填充或孔口堵塞的影响，因为形成了更高摩尔体积的CaSO4。对其他碳酸盐的研究表明，它们的煅烧孔隙率更高的部分位于较小的孔隙中，这导致硫酸盐提前终止。结果表明，内部孔结构对初始反应活性和最终脱硫剂转化率的影响。
A modified CaCO3 sorbent with an open internal pore structure is prepared and its sulfation characteristics are investigated in an entrained flow reactor at high temperatures (900-1,100°C) and short contact times (20–600 ms) using small particle sizes (< 5 μm). The most distinguishing feature of this modified carbonate (MC) is its 70–75% sulfation conversion within 0.5 s, which is substantially higher than any other sorbents published. The MC is prepared by carbonation-precipitation from a calcium hydroxide suspension by optimizing the operating parameters to generate carbonate particles of the desired pore structural properties. The high initial surface area combined with its open pore structure and pore-size distribution of its calcine contribute to its high reactivity. The calcined MC possesses a significant portion of its pore volume in the 50-200 A range. This size range represents an optimum pore size for sulfation since it provides a reasonably high surface area and is less susceptible than < 50 A pore sizes, to pore filling, or pore-mouth plugging due to the formation of higher molar volume CaSO4. Investigation with other carbonates reveals that a much higher portion of their calcines' porosity lies in the smaller pores, which leads to premature termination of sulfation. Results show the impact of internal pore structure on initial reactivity and ultimate sorbent conversion.